Back to 2015: EPA Proposes to Eliminate Limits on Power Plants’ Greenhouse Gas Emissions

Last week, we blogged about the Environmental Protection Agency’s (EPA) proposed revocation of limits on coal-fired electric generating units’ (EGUs) emissions of hazardous air pollutants.  

That isn’t all EPA has been up to.  

On the same day EPA proposed to revoke limits on coal-fired EGUs’ emissions of hazardous air pollutants, it also published a proposal to eliminate all limits on fossil fuel-fired EGUs’ greenhouse gas emissions.

That proposal would bring EPA’s regulation of EGUs’ greenhouse gas emissions back full circle to where it was 10 years ago, specifically, to no regulation of such emissions.  

The Presidential administrations over the last 10 years have gone back and forth (and back and forth again) in their attempts to regulate, or not regulate, GHG emissions from EGUs. 

Here is a timeline of the highlights of what EPA and the courts have done with respect to the regulation of EGUs’ GHG emissions. 

See if you can follow:

In 2015, the EPA under President Obama promulgated New Source Performance Standards for yet-to-be-built fossil fuel-fired EGUs (the NSPS) and the Clean Power Plan for existing fossil fuel-fired EGUs. 

The NSPS would have required new fossil fuel-fired EGUs to use carbon capture and sequestration to limit their GHG emissions.  

The Clean Power Plan would have required the states to regulate greenhouse gas emissions by shifting generating capacity from fossil fuel-fired EGUs to renewable generation of electricity.  

Notably, the EPA asserted that it had the authority to promulgate the NSPS and the Clean Power Plan under section 111 of the Clean Air Act based on its determination that fossil fuel-fired EGUs were a significant source of GHG emissions and its 2009 determination that GHG pollution endangered the public health and welfare.  Section 111 requires EPA to regulate emissions from a category of sources if such emissions “cause[], or contribute[] significantly to, [dangerous] air pollution.”

In 2018, the EPA under President Trump proposed to revise the NSPS for fossil fuel-fired EGUs by eliminating the Clean Power Plan’s carbon capture and sequestration requirement.

In 2019, the EPA under President Trump repealed the Clean Power Plan and replaced it with the Affordable Clean Energy Rule.  

The Affordable Clean Energy Rule would have required new coal-fired EGUs to reduce GHG emissions by improving combustion efficiency and would also have eliminated the requirements that would have required the states to shift generation capacity from fossil fuel-fired EGUs to renewable generation of electricity.

In 2021, the U.S. Court of Appeal for the District of Columbia Circuit vacated both the Affordable Clean Energy Rule and the Trump Administration’s repeal of the Clean Power Plan.

 In 2022, in the case West Virginia v. EPA, the U.S. Supreme Court reversed the D.C. Circuit’s decision to vacate the repeal of the Clean Power Plan, determining that section 111 of the Clean Air Act could not be read so expansively as to give EPA the power to restructure the United States’ market for electricity.  

Following that reversal, the D.C. Circuit entered an order which would have reinstated the Affordable Clean Energy Rule, which never went into effect because…

In 2024, the EPA under President Biden responded to the Supreme Court’s decision by promulgating the “Carbon Pollution Standards,” which repealed the Affordable Clean Energy Rule.  

The Carbon Pollution Standards also would have required coal-fired EGUs to use carbon capture and sequestration after January 1, 2032, and would have imposed strict limits on GHG emissions from natural gas- and oil-fired EGUs.

And finally, on June 17, the EPA (once again under President Trump) proposed not just to repeal the “Carbon Pollution Standards,” but also all GHG emission standards for fossil fuel-fired EGUs.  

In this proposal, EPA departs from the interpretation of section 111 of the Clean Air Act that it used in 2015 to assert its authority to regulate EGUs’ GHG emissions.  Rather than focusing on the volume of those emissions alone to determine whether or not they contribute “significantly” to dangerous air pollution, EPA proposes to focus on the impact that regulating the emissions would have on the public health and welfare.  

Specifically, EPA asserts that because GHG pollution is a global problem that EGUs in the United States contribute to in only a small (and shrinking) part, and because its regulation of American EGUs’ GHG emissions would have no significant effect on GHG levels in the atmosphere, those emissions do not cause or significantly contribute to dangerous levels of GHG pollution, and it is not obligated to regulate them under Clean Air Act Section 111.  

 Which returns the status quo to where it was in 2015. 

 “If you are thinking that EPA’s assertion regarding the scope of its regulatory authority, if taken as true, would mean no regulation of any GHG emissions under the Clean Air Act as it is currently written, you may very well be right,” said GASP’s Senior Attorney John Baillie. “Moreover, if you’re wondering why no one in Congress or the White House thought to amend the Clean Air Act at any time between 2015 and now to clarify how GHG emissions from EGUs and other sources should be regulated – there have been several years where one party or the other controlled both Congress and the White House – so are we.  It is a remarkable failure.”

It is just about certain that EPA will promulgate a final rule regarding EGUs’ GHG emissions based on the latest proposal in the upcoming months or years, and similarly certain that the basis of the final rule will be challenged in court.  We will follow along and keep you posted on that.  In the meantime, EPA is accepting comments on its proposed rule through Aug. 7.  

You can submit comments at https://www.regulations.gov.  

Submit your comments under Docket ID No. EPA-HQ-OAR-2025-0124, and reference that docket number in your comments themselves.